1. Field of the Invention
This invention relates to improved sets of sealing blades for a shrink wrapping process and, more specifically, to such sealing blades which are utilized to join two sheets of heat-shrinkable polyethylene prior to it being heated to cause shrinkage thereof for sealing an object therein.
2. Description of the Prior Art
It is well known that objects can be sealed in heat-shrinkable polyethylene by a process in which the object is initially placed between two sheets of polythylene prior to its being eventually heated for shrinkage. In this process, the object is advanced along with and between two long sheets of heat-shrinkable polythylene which are normally supplied in large rolls. Each object is advanced beneath a sealing and cutting device which is used to partially encase the object by temporarily sealing the leading and trailing edges of the sheets at either end of the object prior to being advanced for eventual shrinkage. Heretofore, one set of sealing blades was utilized to seal at the trailing said of one object as another set of sealing blades sealed the sheets at the leading side of the adjacent object with the two sheets being cut between the adjacent seals. However, the prior art sealing blades were straight and extended transversely of the long sheets of polyethylene. As a result, the sides of the temporary package containing the object were left open and it was not uncommon for the object located between the leading seal and the trailing seal to be capable of movement transversely between the two sheets. When the object was transferred for heating and shrinking of the polyethelene in this temporarily wrapped manner, if the object were off center, there was no guarantee that the polyethylene would properly shrink around the object to produce a complete, effective seal.